KR20060077556A - Apparatus for preventing over voltage and leakage current - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to an overvoltage and leakage current blocking device.

2. The technical problem to be solved by the invention

According to the present invention, when the voltage applied from the external device is greater than or equal to the threshold voltage (overvoltage), the overvoltage is blocked by using the overvoltage blocking means, and the current consumption is reduced by blocking the current leaked through the body diode of the overvoltage blocking means. To provide an overvoltage and leakage current blocking device which can be used.

3. Summary of Solution to Invention

The present invention provides an overvoltage and leakage current blocking device comprising: overvoltage detection means for outputting a power supply signal or an overvoltage cutoff control signal depending on whether an overvoltage of a power supply applied through an external power supply means; Overvoltage blocking means for protecting an internal circuit from an overvoltage by applying or blocking power applied through the external power applying means according to a power applying signal or an overvoltage blocking control signal received from the overvoltage detecting means; And a leakage current blocking means provided between the external power applying means and the overvoltage blocking means to block a current leaking through the overvoltage blocking means from a power supply means for supplying power to the internal circuit.

4. Important uses of the invention                 

The present invention is used in electronic devices and the like.

Overvoltage Lockout, Leakage Current Lockout, Schottky Diodes, Internal Circuit Protection

Description

Apparatus for preventing over voltage and leakage current             

1 is a configuration diagram of a portable terminal having a conventional overvoltage blocking function;

2 is a configuration diagram of another embodiment of a portable terminal having a conventional overvoltage blocking function;

3 is a block diagram of an embodiment of a portable terminal having an overvoltage and leakage current blocking function according to the present invention;

4 is a configuration diagram of another embodiment of a portable terminal having an overvoltage and leakage current blocking function according to the present invention.

* Explanation of symbols for the main parts of the drawings

31: kit 32: overvoltage detector

33: leakage current breaker 34: overvoltage breaker

35 battery 36 poly switch (or fuse)

37: control unit (MSM)

The present invention relates to an overvoltage and leakage current blocking device, and more particularly, to block an overvoltage using an overvoltage blocking means, as the voltage applied from an external device is greater than or equal to a threshold voltage (overvoltage), and the body of the overvoltage blocking means. An overvoltage and leakage current blocking device, which can reduce current consumption by blocking current leaking through a diode.

Hereinafter, the present invention will be described by taking a portable terminal having an overvoltage and leakage current blocking function as an example.

In the present invention, the portable terminal refers to a wireless communication terminal, a personal digital assistant (PDA), a portable computer (laptop), a portable multimedia player (PMP), and the like.

The wireless communication terminal is a mobile communication terminal, a personal digital communication terminal (PCS), a personal digital terminal (PDA), a smart phone, a next generation mobile communication terminal (IMT-2000), wireless communication while being carried by an individual such as a wireless LAN terminal. Say this is possible terminal.

For example, a wireless communication terminal has various functions in addition to a call function, which is an original purpose, for example, a wireless communication terminal equipped with a digital camera, a wireless communication terminal having an MP3 (MP3) player function, and a GPS reception function. And a wireless communication terminal equipped with a. In addition, the popularity of wireless communication terminals has become very common, and various convenient functions are expected to be added because of the characteristics that an individual always carries.

In general, a fuse is a device that automatically cuts off a current by melting itself when an excessive current exceeding a specified value flows, and is used to protect an electric device, an electronic communication device, and a wiring from an overcurrent.

On the other hand, poly switch refers to a protection device that replaces a disposable fuse that has been used for overcurrent protection of electronic products. The main feature is that it can be used semi-permanently by adopting an electrically conductive polymer material. The operation principle of the poly switch is as follows. First, when an overcurrent flows into a circuit, a poly switch changes from a low resistor to a high resistor by Joule heat generated by the current, thereby protecting the internal circuit by limiting the overcurrent. After that, if the overcurrent factor is removed and the temperature of the poly switch is lowered, the resistance value is returned to the initial low value and the circuit operates normally.

On the other hand, a Schottky diode is a diode that uses a Schottky gate electrode directly attached to an N-type semiconductor to prevent reverse voltage at the contact surface of a metal and a semiconductor (schottky barrier). It is used for high frequency and general rectification. Dragons are often used for the detection of UHF and microwave bands or for mixers. Schottky diodes for general rectification are used for power rectification of low voltage and high current, because the forward voltage is smaller than the general rectifier diode and the reverse breakdown voltage cannot be too large (currently about 100 ~ 200V). It is also used for high frequency rectification circuits and switching power supplies by utilizing high speed characteristics.

Meanwhile, in the present invention, a body diode refers to a parasitic diode owned by the transistor itself.

Here, a P-channel transistor or an N-channel transistor may be used as the overvoltage blocking unit for blocking the overvoltage. However, since the voltage level of the control signal that the overvoltage detector outputs varies depending on the type of transistor, the internal circuit structure of each overvoltage detector varies accordingly.

1 is a block diagram of an exemplary embodiment of a portable terminal having a conventional overvoltage blocking function.

As shown in FIG. 1, a conventional portable terminal having an overvoltage blocking function may include a power supply signal based on a car kit 11 for connecting an external device to the mobile terminal and whether or not the power applied from the car kit 11 is overvoltage. Alternatively, according to an overvoltage detector 12 for outputting an overvoltage cutoff control signal, a power applying signal received from the overvoltage detector 12 or an overvoltage cutoff control signal, power supplied from the kit 11 is applied to an internal circuit or an overvoltage An overvoltage cut-off unit (P type, body diode) 13 for protecting an internal circuit from overvoltages, a battery 14 for supplying power to the inside of the portable terminal, the kit 11 or the battery 14 As the current received from the over current is a poly switch (or a protection switch) to protect the internal circuit from being applied to the internal circuit And a's) 15, and the control unit (MSM) (16) for driving by receiving the power through the poly-switch 15.

On the other hand, the over-voltage blocking unit 13, the P-channel transistor for applying or blocking the power input from the kit 11 to the control unit 16 in accordance with the control signal received from the over-voltage detection unit 12 106, and its own body diode 107 of the P-channel transistor 106.

Meanwhile, the overvoltage detector 12 receives the bandgap reference 103 for outputting a reference voltage (about 1.2V), and is received from the kit 11 to be compared with the reference voltage of the bandgap reference 103. The bandgap reference 103 and the voltage divided by the first resistor 101 and the second resistor 102, the first resistor 101 and the second resistor 102 to distribute a voltage (about 4.2V). Comparator 104 for comparing the voltage received from the), and a transistor for outputting the power supply signal or the overvoltage cutoff control signal to the gate terminal of the P-channel transistor 106 by receiving the output signal of the comparator 104 Driver 105.

Here, the overvoltage detector 12 determines whether the voltage applied to the internal circuit through the kit 11 exceeds the threshold voltage, and if the threshold voltage does not exceed the threshold voltage, the gate for turning on the P-channel transistor 106. Outputs a low signal to the terminal. Meanwhile, the overvoltage detector 12 outputs a high signal to the gate terminal to turn off the P-channel transistor 106 as the applied voltage exceeds the threshold voltage (overvoltage). In this way, the overvoltage applied to the internal circuit can be cut off.

2 is a block diagram of an embodiment of a portable terminal having a conventional overvoltage blocking function.

As shown in FIG. 2, a conventional portable terminal having an overvoltage blocking function includes a power supply signal based on a car kit 21 for connecting an external device to the mobile terminal and whether or not the power applied from the car kit 21 is overvoltage. Alternatively, according to an overvoltage detector 22 for outputting an overvoltage cutoff control signal, a power applying signal received from the overvoltage detector 22 or an overvoltage cutoff control signal, power supplied from the kit 21 is applied to an internal circuit or an overvoltage An overvoltage cut-off unit (N type, body diode) 23 for protecting an internal circuit from an overvoltage by blocking a voltage, a battery 24 for supplying power to the inside of the portable terminal, the kit 21 or the battery 24. As the current received from the over current is a poly switch (or a protection switch) to protect the internal circuit from being applied to the internal circuit And a's) 25, and a control unit (MSM) (26) for driving by receiving the power through the poly-switch 25.

On the other hand, the over-voltage blocking unit 23, the N-channel transistor for applying or cutting off the power input from the kit 21 to the control unit 26 in accordance with the control signal received from the over-voltage detection unit 22 204, and its own body diode 205 of the N-channel transistor 204.

On the other hand, the overvoltage detector 22 is a voltage detector 201 for detecting the voltage received from the kit 21, so that the voltage sensed by the voltage detector 201 can operate as a power source of the transistor driver 203 A transistor driver 203 for receiving a charge pump 202 for increasing a voltage and an output signal of the charge pump 202 and outputting a power application signal or an overvoltage cutoff control signal to a gate terminal of the N-channel transistor 204. ).

Here, the overvoltage detector 22 determines whether the voltage applied to the internal circuit through the kit 21 exceeds the threshold voltage, and if the threshold voltage does not exceed the threshold voltage, the gate for turning on the N-channel transistor 204. Output high signal to terminal. Here, the N-channel transistor 204 uses the charge pump 202 because the potential of the gate terminal must be higher than the source terminal to turn on. On the other hand, the overvoltage detector 22 outputs a low signal to the gate terminal to turn off the N-channel transistor 204 as the applied voltage exceeds the threshold voltage (overvoltage). In this way, the overvoltage applied to the internal circuit can be cut off.

In general, when the portable terminal receives power from an external device (for example, a computer) instead of being powered from the battery 14, there is a possibility that an overvoltage may be applied. Thus, an overvoltage protection circuit (overvoltage detection section 12 and overvoltage blocking section 13) is used to block the overvoltage from being applied.

Here, the overvoltage detecting unit 12 and the overvoltage blocking unit 13 are designed to operate for the purpose of preventing overvoltage application only when the portable terminal receives power from the car kit 11.

However, the conventional portable terminal may leak current to the overvoltage detector 12 through the body diode 107 of the transistor itself of the overvoltage blocking unit 13 even when power is not received through the car kit 11. However, there is a problem that an additional current consumption occurs.

The present invention has been proposed to solve the above problems, and as the voltage applied from the external device is above the threshold voltage (overvoltage), the overvoltage is blocked by using the overvoltage blocking means, and leakage through the body diode of the overvoltage blocking means. It is an object of the present invention to provide an overvoltage and leakage current blocking device that can reduce current consumption by cutting off the current.

Other objects and advantages of the present invention can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. Also, it will be readily appreciated that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

In the apparatus of the present invention for achieving the above object, in the overvoltage and leakage current blocking device, an overvoltage detection for outputting a power supply signal or an overvoltage cutoff control signal according to whether or not the overvoltage of the power applied through an external power supply means; Way; Overvoltage blocking means for protecting an internal circuit from an overvoltage by applying or blocking power applied through the external power applying means according to a power applying signal or an overvoltage blocking control signal received from the overvoltage detecting means; And a leakage current blocking means provided between the external power applying means and the overvoltage blocking means to block a current leaked through the overvoltage blocking means from a power supply means for supplying power to the internal circuit. It is characterized by.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, whereby those skilled in the art may easily implement the technical idea of the present invention. There will be. In addition, in describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a block diagram of an embodiment of a portable terminal having an overvoltage and leakage current blocking function according to the present invention.

As shown in FIG. 3, the portable terminal having the overvoltage and leakage current blocking function according to the present invention includes a carkit 31 for connecting an external device (for example, a computer) and the mobile terminal, and the carkit 31. The over-voltage detector 32 for outputting a power-applied signal or an over-voltage cutoff control signal according to whether or not the power supply voltage is applied from the power supply, or the power supply signal or the overvoltage cut-off control signal received from the overvoltage detector 32 31 is located between the overvoltage cut-off unit 34, the kit 31 and the overvoltage cut-off unit 34 to protect the internal circuit from the overvoltage by applying power received from the internal circuit or cutting off the overvoltage. Leakage current blocking unit 33 for blocking the current leaked through the over-voltage blocking unit 34 from 35, for supplying power to the portable terminal The poly switch (or fuse) 36 for protecting the internal circuit by preventing overcurrent from being applied to the internal circuit as the current supplied from the battery 35, the kit 31, or the battery 35 is an overcurrent, And a control unit (MSM) 37 for receiving and driving power through the poly switch 36.

Meanwhile, the overvoltage detector 32 receives the bandgap reference 303 for outputting a reference voltage (about 1.2V) and the kit 31 to be compared with the reference voltage of the bandgap reference 303. The bandgap reference 303 and the voltage divided by the first resistor 301 and the second resistor 302, the first resistor 301 and the second resistor 302 to distribute a voltage (about 4.2V). Comparator 304 for comparing the voltage received from the) and a transistor for outputting the power supply signal or the overvoltage cutoff control signal to the gate terminal of the P-channel transistor 306 by receiving the output signal of the comparator 304 Driver 305.

On the other hand, the leakage current blocking unit 33 is characterized in that the Schottky diode (Schottky Diode).

Here, the overvoltage detector 32 determines whether the voltage applied to the internal circuit through the kit 31 exceeds the threshold voltage, and if the threshold voltage does not exceed the threshold voltage, the gate for turning on the P-channel transistor 306. Outputs a low signal to the terminal. Meanwhile, the overvoltage detector 32 outputs a high signal to the gate terminal to turn off the P-channel transistor 306 as the applied voltage exceeds the threshold voltage (overvoltage). In this way, the overvoltage applied to the internal circuit can be cut off.

4 is a configuration diagram of another embodiment of a portable terminal having an overvoltage and leakage current blocking function according to the present invention.

As shown in FIG. 4, the portable terminal having the overvoltage and leakage current blocking function according to the present invention includes a kit 41 for connecting an external device (eg, a computer) and the portable terminal, and the kit 31. The over-voltage detector 42 for outputting a power-applied signal or an over-voltage cutoff control signal according to whether or not the power supply voltage is applied from the power supply, or the power supply signal or the over-voltage cut-off control signal received from the overvoltage detector 42. It is located between the overvoltage cutout 44, the kit 41 and the overvoltage cutout 44 to protect the internal circuit from the overvoltage by applying the power received from the 41 to the internal circuit or cut off the overvoltage Leakage current blocking unit 43 for cutting off the current leaked through the over-voltage blocking unit 44 from the 45, to supply power to the inside of the portable terminal A poly switch (or fuse) 46 for protecting an internal circuit by preventing an overcurrent from being applied to the internal circuit as the current supplied from the battery 45, the kit 41, or the battery 45 is an overcurrent, And a control unit (MSM) 47 that receives and drives power through the poly switch 46.

On the other hand, the overvoltage detector 42, the voltage detector 401 for sensing the voltage received from the kit 41, the voltage sensed by the voltage detector 401 can operate as a power source of the transistor driver 403. A transistor driver configured to receive the output signal of the charge pump 402 and to output a power supply signal or an overvoltage cutoff control signal to a gate terminal of the N-channel transistor 404. 403).                     

On the other hand, the leakage current blocking unit 43 is characterized in that the Schottky diode (Schottky Diode).

Here, the overvoltage detector 42 determines whether the voltage applied to the internal circuit through the kit 41 exceeds the threshold voltage, and if the threshold voltage does not exceed the threshold voltage, the gate for turning on the N-channel transistor 404. Output high signal to terminal. Here, the N-channel transistor uses the charge pump 402 because the potential of the gate terminal must be higher than the source terminal to turn on. On the other hand, the overvoltage detector 42 outputs a low signal to the gate terminal to turn off the N-channel transistor 404 as the applied voltage exceeds the threshold voltage (overvoltage). In this way, the overvoltage applied to the internal circuit can be cut off.

In the present invention, the transistor used as the overcurrent blocking unit in the above-described embodiments and other embodiments has been described using a metal-oxide semiconductor field effect transistor (MOSFET) as an example, but a bipolar junction transistor (BJT) Bipolar junction transistors), but is not limited thereto.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

In the present invention as described above, as the voltage applied from the external device is more than the threshold voltage (overvoltage) by blocking the overvoltage using the overvoltage blocking means, by blocking the current leaking through the body diode of the overvoltage blocking means, This can reduce the current consumption.

Claims (2)

In the overvoltage and leakage current blocking device, Overvoltage detecting means for outputting a power applying signal or an overvoltage cutoff control signal depending on whether an overvoltage of a power applied through an external power applying means; Overvoltage blocking means for protecting an internal circuit from an overvoltage by applying or blocking power applied through the external power applying means according to a power applying signal or an overvoltage blocking control signal received from the overvoltage detecting means; And Leakage current blocking means is provided between the external power supply means and the over-voltage blocking means, for blocking the current leaked through the over-voltage blocking means from the power supply means for supplying power to the internal circuit Overvoltage and leakage current blocking device comprising a. The method of claim 1, The leakage current blocking means, Overvoltage and leakage current blocking device, characterized in that the Schottky Diode (Schottky Diode).

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